An electronic computing device, such as a smartphone or tablet computer, is assembled from a variety of individual electronic components, each of which are tested during manufacturing. During testing, the components must function within an acceptable performance range to be considered a passing component. However, even among passing components, there may still be some variation in the quality of the component output, as long as the variation is within acceptable tolerance. To compensate for the variation within the acceptable tolerances, the collection of performance data that is gathered during component testing is used to adjust the output or input or both input and output of the components during the operation of the electronic device.
Once a complete electronic computing device is assembled from the individual components, the device undergoes additional testing, and additional calibration data is gathered and used to correct for errors created by signal variances due to the combined tolerances of the many components within the assembled electronic device. For example the gain of the antennas of the wireless communication interface of a device is set or adjusted, internal voltage references are programmed, audio volumes are calibrated, and the display contrast is configured to a suitable default level. Additionally, if a device is to access a particular wireless communication network, such as a mobile phone radio network, the device is provisioned to communicate over the network, and the wireless radio system is configured and calibrated, as proper radio frequency calibration for the wireless baseband processor is essential for ensuring that each device meets the regulatory requirements prescribed by the various communications regulatory agencies. Moreover, any sensors, such as accelerometers, gyroscopes, or magnetometers that are contained within the electronic device are calibrated when manufacturing the individual components, during device manufacturing, or both.
In some devices the calibration and provisioning data is stored within dedicated nonvolatile memory devices, such as serial NOR flash EEPROM devices that are integrated within the components of the device. The dedicated storage devices within the components allow the components' manufactures to store calibration data generated during the manufacturing process. The dedicated storage devices (within the component) also provide a manner of physical security for the calibration and provisioning data, as the dedicated memory devices storing the calibration and provisioning information are only accessible using specialized equipment and access methods, which renders the factory data essentially inaccessible outside of the factory environment.
However, the added expense of the dedicated memory within each component increases the manufacturing cost, which will be reflected either at the component manufacturing level, the device manufacturing level, or both. Additionally, it may not be cost effective to include sufficient dedicated nonvolatile memory to store the desired amount of calibration data, either for the individual component or for the assembled device. Accordingly, the currently available calibration and device provisioning data must be small enough to occupy the limited amount of dedicated non-volatile memory assigned to store the calibration and provisioning data for the component.